Computer systems are fundamentally comprised of subsystems for storing and retrieving information, manipulating information, and displaying information. Nearly all computer systems today use optical, magnetic or magneto-optical storage media to store and retrieve the bulk of a computer system's data. Successive generations of ever more powerful microprocessors, and increasingly complex software applications that take advantage of these microprocessors, have driven the storage capacity needs of systems higher and have simultaneously driven read and write performance demands higher. Magnetic storage remains one of the few viable technologies for economically storing large amounts of information with acceptable read and write performance.
Market pressures place ever greater demands on hard disk drive manufacturers to reduce drive costs. To maintain market advantage, new hard disk drive designs typically incorporate greater efficiency in device operating tolerances or manufacturability.
There are basic components common to nearly all hard disk drives. A hard disk drive typically contains one or more disks clamped to a rotating spindle, a head for reading or writing information to the surface of each disk, and an actuator assembly utilizing linear or rotary motion for positioning the head for retrieving information or writing information to a location on the disk. A rotary actuator is a complex assembly that couples the head to a pivot point that allows the head to sweep across the surface of the rotating disk. The assembly typically couples the head to a flexible member called a suspension, which is then coupled to the pivotally mounted actuator assembly.
The pivoting motion of a rotary actuator is achieved with minimal friction by connecting the actuator assembly with a bearing assembly such that the actuator assembly does not slip relative to the pivoting portion of the bearing assembly. Common methods of connecting an actuator assembly with a bearing assembly are typically cumbersome and risk contamination, or are not suitable for smaller bearing assembly diameters.